I have a 2001 F350 and my service engine soon light came on. For a while it went on and off and every time it came on the engine ran rough and I lost some power. I pulled the valve covers and checked the UCVH and everything was fine that I can tell I even made the shims out of quarters and put them in. After putting it all back together its still doing the same thing. Any suggestion.

 

The harness that goes over the driver side valve cover can chafe against the cover, leading to random shorts. Loosen the bolt holding the 42 pin connector together (big square plug where chassis harness mates to engine harness) pull it apart and have a look at the bottom of the harness. If bare wires apply some tape or something and reinstall. Split heater hose makes good protection against further chaffing.

Just a shot in the dark there. Does the issue correlate to anything? Rough road, time of day, location, temp, whatever.

Oil level good?

And welcome to FTE!